Paving material.



J. S. E. PARDBE. PAVING MATERIAL.

APPLICATION FILED FEB 1a 1913.

Patented Mar. 10, 191i IN VENTOR a E m w %Q)ATTORNEY UNITED STATES PATENT OFFICE.

JOHN S. E. PAR-DEE, OF PHILADELPHIA. PENNSYLVANIA.

PAVING MATERIAL.

To all whom it may concern:

Be it known 'that I, JOHN S. E. PARDEE, a citizen of the United States, residing in the city of Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in Paving Material, of which the following is a specification.

My invention relates to improvements in pavements for streets, roads, side'walks, etc., which shall withstand the impacts and wear incident to traffic and which shall find its greatest use in places and under circumstances in which bituminous concrete, bituminous macadam, sheet asphalt and like pavements have heretofore been commonly used.

I have found that the principal cause of failure in street pavin surfaces composed of mineral aggregates bound together by a plastic bituminous compound has been due to a lack of permanence or continuance of resiliency and plasticity; and I have found that to maintain these qualities which would then give almost perpetual life to a paving surface, some method or materials must be employed whereby the stability may he attained without sacrificing elasticity or resiliency. One present form of construction largely used depends upon the inherent stability of a graded mineral aggregate and upon the reduction to a minimum of the voids or interstices between the component crushed stone, gravel or the like and the binding together of such components and filling the voids by a plastic compound of bituminous cement. A disadvantage of such construction I have found to be due to the fact that such a dense homogeneous mixture is so obtained that after such a wearing surface has attained its ultimate set there is so little'yielding or elasticity that a rapid deterioration by abrasion from traffic results. I have also found that those sheet asphalt pavements which exclude from their construction all larger particles of sand and gravel and which are composed largely of sand with the interstices filled with a bituminous I cement, require excessive maintenance because it is difficult to manufacture, blend, mix or flux a bituminous cement sutliciently rigid to withstand traflic at the higher temperatures of the summer months and which will not be so brittle at the lower temperatures of the winter months as to crystallize, crack, break .up and crumble Specification of Letters Patent.

Application filed February 13, 1913.

Patented Mar. 10, 1914.

Serial No. 748.063.

from the effects of frost, heavy traffic, etc. It is also common practice in road building to use bitumen as a binder for the mineral ingredients and to allow a minimum percentage of void.

In contra-distinction to established practices, I do not rely upon unusual strength of the bond between the organic and mineral components of my paving composition; and the principle of inherent stability of the mineral aggregate, if utilized in my form of pavement, would be destructive of the ends desired, namely, permanency of life due. to the continuance of those elastic and resilient qualities which are present in a newly constructed bituminous mortar pavement. The employment of mineral components in my pavement is more for the purpose of lending greater solidarity and rigidity to the hereinafter described bituminous organic component which, despite the fact that if used alone would afford a durable wearing surface, would possess such excessive elasticity as to cause unusual resistance to traction and produce discomfort to those riding in vehicles passing over such pavement.

By my invention I use as a means of securing long continued resiliency and elasticity and of insuring permanent vitality to the compound, organic matter, preferably saw-dust, which, after being thoroughly seasoned and dried, is intimately mixed with a preservative such as oil, preferably a creosote, or a blend of creosote with bituminous cement such as tar, asphaltum or other suit able bitumen.. I prefer to incorporate with the mixture of organic matter and preservative, such as referred to, commercial lime, chalk, marl or finely sifted ashes, the mixture being kept constantly in motion in suitable mixing or stirring apparatus at a temperature of 140 to 180 degrees centigrade, more or less, until it becomes homogeneous. To this mixture of organic matter or conglomerate is now added at a like temperature av mineral aggregate, coated or not with bituminous or other cement, of gravel or stone composed of approximately three parts, by volume, of mineral aggregate to one part of the organic mixture. This mixtureof organic refuse, calcium compound, bituminouscement and mineral aggregate is then placed upon a suitable foundation or concrete, broken rock or ordinary macadam and compacted under a roller. Or the composition may be manufactured in blocks to be used as paving blocks as has heretofore been done with granite, asphalt or creosoted wood-blocks, or vitrified bricks.

In the case where my composition is used in mass for laying a pavement in sheet form, a surface finish may be used to secure greater stability and to serve as a seal coat to prevent vaporization and escape of the preservative and organic oils, etc. is preferably made of a bituminous cement of proper consistency to be flexible when cold and such coat is preferably applied as soon as possible after the rolling of my mix ture is finished at a temperature of from 150 to 180 degrees centigrade, more of less, and evenly spread; On top of this seal coat may be applied a top dressing of torpedo sand, fine gravel or stone chips thoroughly dried and preferably heated, which is then preferably thoroughly rolled.

For an illustration of one of the forms my invention may take reference is to be had to the accompanying drawing, in which:

Figure 1 is a cross sectional view of a street, road or side-walk embodying my invention. Fig. 2 is a fragmentary sectional View, on somewhat larger scale, illustrating a form of my invention.

In Fig. 1, C, C may represent curb stones or the like forming lateral boundaries for the pavement. The lower layer A may be of any suitable material such as concrete, broken rock or stone, or ordinary macadam, such layer serving as a foundation for the pavement. Upon this foundation layer is rolled or compacted the layer B comprising my improved composition of organic matter, preservative, mineral aggregate, etc., as above described. Upon the layer B is compacted or roll-ed the top or seal coat D hereinbefore referred to. In Fig. 2 a fragment of the layers B and D are shown on somewhat larger scale. As to the layer Bit will be noted that the percentage of volume occupied by the broken stone or mineral aggregate M is relatively smaller than with the common forms of pavements hereinbefore referred to, and that the percentage of filler F, of organic matter, preservative, bituminous cement, lime, etc., hereinbefore described, is relatively larger than in such common forms of pavements referred to. It will thus be seen that my improved pavement composition consists of the filler F having therein the mineral aggregate M pre; pared as hereinbefore described.

In place of saw-dust as a component of the filler. F may be used wood pulp, paper mash,

wood chips, paper pulp, timberby-products, vegetable or timber fiber or similar cellulosic or organic material. And as the mineral aggregate M for the paving composition may be used broken stone, crushed rock, gravel,

Such seal coat Loeaoe'a stone dust, sand, trap-rock, limestone, granite, and the like.

The filler F possesses the desirable qualities of resiliency and elasticity which are particularly advantageous when the filler F forms so large a percentage of the entire mixture of filler and mineral aggregate. Furthermore the filler in this instance, though comprising bituminous cement, does not act as a binder between separate particles or pieces of the mineral aggregate as has been the function of the bituminous cement and mixed with bituminous material, and a mineral aggregate having relatively large voids filled therewith.

2. As a paving material, a filler of cellulosic material treated with creosote and mixed with bituminous material, and a coarse mineral aggregate having relatively large voids filled therewith.

3. As a'paving material, a filler of creosoted sawdust and asphaltum, and a mineral aggregate having relatively large voids filled therewith.

i. As a paving material,'a filler comprising a mixture of cellulosic material with bituminous material, and a course mineral aggregate having voids filled with said mixture, said filler having a volume approximately one-third of that of said mineral aggregate.

5.'As a paving material, a filler comprising a mixture of cellulosic material treated with a preservative, oil and mixed with bituminous matter, and a coarse mineral aggregate 'having relatively large voids filled with said mixture.

6. As a paving material, a mixture of cellulosic material, bituminous matter and a calcium compound, and a coarse mineral aggregate having relatively large voids filled with said mixture.

7. As a paving material, a,filler of cellulosic material treated with creosote and mixed with asphaltum, and a mineral aggregate having relatively large voids filled with said mixture.

8. As a paving material, a mineral aggregate, and a filler for the relatively large voids in said mineral aggregate comprising a mixture of cellulosic material treated with non-bituminous preservative with a bitumen.

9. As a paving material, a'miner'al aggregate coated witha bituminous cement, and a.

ller for the relatively large voids in said vmineral aggregate comprising cellulosic voids filled with said filler, said filler having a volume approximately one third the volume of said mineral aggregate.

11. As a paving material, a filler comprising oellulosic material treated with a preservative oil and mixed with bituminous material, and a mineral aggregate havin more than twice the volume of said filleraving voids filled with said filler.

12. As a paving material, a filler compr1s ing creosotedicellulosic material mixed with bituminous material, and a coarse mineral aggregate having voids filled with said filler, said mineral aggregate having a volume greater than said filler.

In testimony .whereof I have hereunto afiixed my signature in the presence of the two subscribing witnesses.

JOHN S. E. PARDEE.

Witnesses:

NELLIE EVANS ELEANOR T. MCGALL. 

